Method for air-conditioning a vehicle interior dependent on incident sunshine

ABSTRACT

A method for the air conditioning of a vehicle interior as a function of incident solar radiation. In a vehicle with, for example, a four-zone air conditioning system, the incident solar radiation is detected by means of sensor elements assigned to the various air conditioning zones in the vehicle and is used for regulating the air conditioning capacity. In order to avoid faulty regulation due to a detected incident solar radiation which does not influence or only slightly influences the passengers because of perpendicular incident radiation, for example, on the roof, the hood and the trunk lid, the incident radiation direction is determined by means of the sensor elements and the regulation of the air conditioning capacity is adapted correspondingly, so that the situation of too intensive cooling, for example in the case of perpendicular radiation on the vehicle roof, is avoided.

This application claims priority to International Patent Application No.PCT/EP2003/012302, filed Nov. 5, 2003, designating the United States ofAmerica, and German Application DE 102 56 866.9 filed on Dec. 4, 2002,the entire disclosure of which is incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for the air conditioning of a vehicleinterior as a function of incident solar radiation.

German patent document DE 40 24 431 A1 discloses an air conditioningsystem with an incident solar radiation sensor arrangement having aplurality of sensor elements. In this case, first, the intensity anddirection of the incident solar radiation are determined from theindividual sensor output signals, after which these two variables servefor controlling an air conditioning system and further vehicle-sideassemblies.

Also in a circuit arrangement, known from German patent document DE 4305 446 A1, which includes an incident solar radiation sensor arrangementhaving a plurality of sensor elements. The intensity and direction ofthe incident solar radiation are first determined from individual sensorelement output signals, after which these two variables serve forcontrolling an air conditioning system and further vehicle-sideassemblies.

U.S. Pat. No. 4,760,772 likewise discloses an air conditioning systemwith an incident solar radiation sensor arrangement having three sensorelements, of which one is assigned to the vehicle front region and theother two are assigned to the two vehicle side regions or alternativelyhaving four sensor elements, of which one is assigned to the vehiclefront region, one is assigned to the vehicle rear region and the othertwo are assigned to the two vehicle side regions. In each case theintensity and direction of the incident solar radiation are determinedfrom the sensor element output signals by means of a following computerunit, so that the air conditioning capacity of the air conditioningsystem can be set differently for various vehicle interior regions bymeans of these two calculated variables.

In U.S. Pat. No. 5,186,682, as in U.S. Pat. No. 4,760,772, the signalfrom two lateral incident solar radiation sensors of a common airconditioning unit is evaluated in terms of the intensity and directionof incidence of the sunlight. The single air conditioning controllerunit then activates the existing air conditioning ducts as a function ofthe determined intensity and direction of the incident solar radiation.

Finally, German patent document DE 195 44 893 C2 discloses an airconditioning system for the air conditioning of a vehicle interior as afunction of incident solar radiation, with at least two air conditioningducts of individually controllable air conditioning capacity for the airconditioning of different vehicle interior regions, and with an incidentsolar radiation sensor arrangement having a plurality of sensor elementsfor detecting the incident solar radiation in different solid angleranges. Each air conditioning duct is individually assigned its ownsensor element of the incident solar radiation sensor arrangement andits own air conditioning controller unit. The sensor element assigned ineach case detects the incident solar radiation essentially with arestriction to that solid angle range which corresponds positionally tothe vehicle interior region air-conditioned by the respective airconditioning duct. The air conditioning controller unit assigned in eachcase sets the air conditioning capacity of the respective airconditioning duct as a function of the output signal from only theassigned sensor element of the incident solar radiation sensorarrangement.

Thus, by means of this prior art, an individual air conditioning ofvarious regions of the vehicle interior as a function of incident solarradiation is possible.

However, the incident solar radiation sensor arrangement supplies onlythe solar values of the individual zones and the average value of these.The solar value of the individual zones is in this case used directly asa factor characteristic curve for temperature or blower regulation as afunction of the outside temperature. That is the blown-air temperatureis lowered as a result of the Sun's influence or the blower level israised. This does not allow for whether the Sun is high or low withrespect to the vehicle.

When the Sun is very high, all the values of the sensor elements of theincident solar radiation sensor arrangement have approximately the samevalue. Depending on the strength of the incident radiation, the valuesare higher or lower. In complete darkness, the sensor values indicate0%, while, in the case of very strong incident solar radiation, thesensor values indicate a maximum of 125%. In the case of a very highsolar load and when the Sun is very high, this means, for airconditioning regulation, that, although there is no incident solarradiation acting on the vehicle occupants since the incident solarradiation takes place on the vehicle roof and not through a window intothe interior, in all the zones the blow-out temperature is lowered verysharply or the blower fraction is increased very sharply as a result ofthe incident solar radiation. This air conditioning regulation, however,is faulty and is very uncomfortable for the occupant/occupants.

The object of the present invention is, therefore, to develop thegeneric air conditioning system for the air conditioning of a vehicleinterior as a function of incident solar radiation and a method foroperating the air conditioning system in such a way that theabovementioned faulty air conditioning regulation which is veryuncomfortable for the occupant/occupants is eliminated.

As a result of the calculation of the steepness of the sunlight or ofthe laterally specific incident solar radiation, it is possible, duringautomatic blower operation, to react to and counteract in a more focusedmanner the influencing factors/disturbing variables acting on thevehicle from outside, such as, for example, incident solar radiationfrom one side or steeply angled sunlight. The occupants, by manualaction, can set the blower even more individually to their requirements.A marked improvement in air conditioning comfort is thereby achieved forthe individual seat positions.

This and further objects, features and advantages of the presentinvention become obvious for the following description of a preferredexemplary embodiment of the invention, in conjunction with the drawingin which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an illustration of the sunlight steepness calculatedaccording to the invention and of a factor, assigned to respectivesunlight steepness, for varying the air conditioning regulation.

FIG. 2 is a schematic illustration of air conditioning component andsensor arrangements in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, the steepness of the sunlight is calculatedby calculating the various solar values of the individual zones. Thecalculation of the sunlight steepness determines whether or not theincident solar radiation is acting on the occupants. With the aid of thesunlight steepness, a corresponding correction factor is determined, bymeans of which a highly accurate compensation of the blown-airtemperature or of the blower increase due to the incident solarradiation is possible.

The method for calculating the sunlight steepness is described in moredetail below. In this case, the explanation is made by the example of afour-zone air conditioning system, as schematically shown in FIG. 2, butmay be applied likewise to other multizone air conditioning systems withmore or fewer zones.

First, the incident solar radiation is detected in different solid angleranges, using four sensor elements 1 a to 1 d, for example of afour-quadrant sensor. The sensor elements are in this case arranged insuch a way that, for example, the first sensor element 1 a detects thevehicle region at front right of vehicle 10, the second sensor element 1b the vehicle region at front left, the third sensor element 1 c thevehicle region at rear right and the fourth sensor element 1 d thevehicle region at rear left and are assigned to corresponding airconditioning regions 2 a-2 d in the vehicle, each of the airconditioning regions having a corresponding air conditioning duct 3 a-3d fed by a blower and air distribution arrangement 4 which can vary theamount of air conditioning delivered to each duct.

Thereafter, taking into account output signals A1 to A4 from the firstto fourth sensor elements 1 a to 1 d and an arithmetic average value Aemitted by the solar sensor, a sunlight steepness S is calculated.

This sunlight steepness S may be calculated, for example, according tothe following formula: S=((|A2−A3|+|A1−A4|)/2*M/ A , S being thesunlight steepness, A2 the output signal from a second sensor element 1b (FL), A3 the output signal from a third sensor element 1 c (RR), A1the output signal from a first sensor element 1 a (FR), A4 the outputsignal from a fourth sensor element 1 d (RL), M a multiplier and A thearithmetic average value of the output signals A1 to A4 from the firstto fourth sensor elements.

The multiplier M amounts, for example, to 50 and is used in order toobtain a greater and therefore more easily illustratable value. Theformula for calculating the sunlight steepness S is organized in such away that S becomes the higher, the lower the angle of the incident solarradiation is. A Sun with a low angle of incident radiation and with ahigh value of sunlight steepness impinges upon more window areas andtherefore requires more air conditioning and therefore higher airconditioning. Furthermore, by the sunlight steepness being calculatedaccording to the invention, it is possible to reduce the probability oferror, since, in the case of lower-angled incident radiation andtherefore lower sensor output signals, the sunlight steepness becomesgreater even in diffuse light, hazy weather and/or the brief effect ofsunlight, and consequently minor errors cannot have such a greatinfluence.

Subsequently, with the aid of the calculated sunlight steepness S, acorrection factor K is determined which is applied to the airconditioning regulation values, such as, for example, the blow-intemperature and/or the blower power, which are calculated by the use ofthe sensor values, conventionally using a four-quadrant sensor, as arule the blow-in temperature being lowered and the blower power beingraised. FIG. 1 shows the profile of a correction factor K of this typein relation to the sunlight steepness S calculated by means of theformula according to the invention. The profile of the correction factorK is in this case vehicle-dependent and design-dependent, since, forexample, influences of varying magnitude occur on the occupants in thecase of window areas or window tilts of different size.

It is evident from FIG. 1 that, below a first threshold value S1 of thesunlight steepness, for example 10, a constant low connection factor,0.4 in the example, is used, since incident solar radiation is verysteep from above here, but insignificant changes do not lead to anyappreciable changes in the influence on the occupants. Consequently, toimprove comfort, conventionally calculated air conditioning regulationvalues are multiplied by the correction factor 0.4, in order tosubstantially reduce the air conditioning variance due to the incidentsolar radiation, since, because of the high steepness, scarcely anyinfluence is exerted on the occupants. Likewise, in a range above asecond threshold value S2 of the sunlight steepness, for example 40, thecorrection factor selected is once again constant, since, with the verylow-angle incident solar radiation on which this sunlight steepness isbased, only insignificant changes in the angle of incidence occur andtherefore require no further adaptation of the air conditioningregulation. In the example, in the case of this very low-angle incidentsolar radiation and therefore high sunlight steepness above the secondthreshold value S2, the correction factor K is set at 1 and the airconditioning regulation values calculated, using the values of thefour-quadrant sensor, are used, unchanged. In the range between thesetwo threshold values S1 and S2, for example, a linear correction factorprofile may be employed, as shown in FIG. 1.

Moreover, an adverse influence of cornerings on the air conditioningregulation is avoided by the sunlight steepness being determinedaccording to the invention.

In summary, the present invention discloses a method for the airconditioning of vehicle interior as a function of incident solarradiation. In a vehicle with, for example, a four-zone air conditioningsystem, the incident solar radiation is detected by sensor elementsassigned to the various air conditioning zones in the vehicle and isused for regulating the air conditioning capacity. In order to avoidfaulty regulation due to a detected incident solar radiation which doesnot influence or only slightly influences the passengers because ofperpendicular incident radiation, for example, on the roof, the hood andthe trunk lid, the incident radiation direction is determined by meansof a sensor element and the regulation of the air conditioning capacityis adapted correspondingly, so that the situation of too intensivecooling, for example in the case of perpendicular radiation on thevehicle roof, is avoided.

1. A method for controlling air conditioning of a vehicle interior as afunction of incident solar radiation, comprising the steps of: detectingincident solar radiation in different solid angle ranges by a pluralityof sensor elements, determining of an air conditioning capacity of atleast two air conditioning ducts of individually controllable airconditioning capacity for the air conditioning of different vehicleinterior regions, the air conditioning capacity of each air conditioningduct being determined, in addition to taking into account an actualinterior temperature, a desired interior temperature, an outsidetemperature and, optionally, a vehicle speed, as a function of an outputsignal from a sensor element assigned to each air conditioning duct orof an averaged output signal from a sensor element assigned to each airconditioning duct, calculating a sunlight steepness according to thefollowing formulaS=((|A2−A3|+|A1−A4|)/2*M/Ā, S being the sunlight steepness, A2 an outputsignal from a second sensor element, A3 the output signal from a thirdsensor element, A1 an output signal from a first sensor element, A4 anoutput signal from a fourth sensor element, M a multiplier and Ā anarithmetic average value of the output signals A1 to A4 from the firstto fourth sensor elements, determining a correction factor with the aidof the calculated sunlight steepness, determining a corrected airconditioning capacity by multiplication of the determined airconditioning capacity by the correction factor, and setting thecorrected air conditioning capacity.
 2. A method for the airconditioning of a vehicle interior as a function of incidence of solarradiation as claimed in claim 1, wherein the correction factor isdetermined as a function of the calculated sunlight steepness in avehicle-dependent manner during measurements.
 3. A method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 2, wherein the correction factor isconstant below a first threshold value of the sunlight steepness andabove a second threshold value of the sunlight steepness, the constantabove the second threshold value being higher than the constant belowthe first threshold value, and the correction factor having a linearprofile between the two threshold values.
 4. The method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 3, wherein during the determination of theair conditioning capacity on the basis of the incident solar radiation,the blow-in temperature is lowered and the blower power is raised, andthis raising/lowering is maintained or reduced by means of thecorrection factor.
 5. The method for the air conditioning of a vehicleinterior as a function of incident solar radiation as claimed in claim3, wherein during the determination of the air conditioning capacity onthe basis of the incident solar radiation, the blow-in temperature islowered or the blower power is raised, and this raising/lowering ismaintained or reduced by means of the correction factor.
 6. The methodfor the air conditioning of a vehicle interior as a function of incidentsolar radiation as claimed in claim 3, wherein the selected multiplieris
 50. 7. The method for the air conditioning of a vehicle interior as afunction of incident solar radiation as claimed in claim 2, whereinduring the determination of the air conditioning capacity on the basisof the incident solar radiation, the blow-in temperature is lowered andthe blower power is raised, and this raising/lowering is maintained orreduced by means of the correction factor.
 8. The method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 7, wherein the selected multiplier is 50.9. The method for the air conditioning of a vehicle interior as afunction of incident solar radiation as claimed in claim 2, whereinduring the determination of the air conditioning capacity on the basisof the incident solar radiation, the blow-in temperature is lowered orthe blower power is raised, and this raising/lowering is maintained orreduced by means of the correction factor.
 10. The method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 9, wherein the selected multiplier is 50.11. The method for the air conditioning of a vehicle interior as afunction of incident solar radiation as claimed in claim 2, wherein theselected multiplier is
 50. 12. A method for the air conditioning of avehicle interior as a function of incident solar radiation as claimed inclaim 1, wherein the correction factor is constant below a firstthreshold value of the sunlight steepness and above a second thresholdvalue of the sunlight steepness, the constant above the second thresholdvalue being higher than the constant below the first threshold value,and the correction factor having a linear profile between the twothreshold values.
 13. The method for the air conditioning of a vehicleinterior as a function of incident solar radiation as claimed in claim12, wherein during the determination of the air conditioning capacity onthe basis of the incident solar radiation, the blow-in temperature islowered and the blower power is raised, and this raising/lowering ismaintained or reduced by means of the correction factor.
 14. The methodfor the air conditioning of a vehicle interior as a function of incidentsolar radiation as claimed in claim 12, wherein during the determinationof the air conditioning capacity on the basis of the incident solarradiation, the blow-in temperature is lowered or the blower power israised, and this raising/lowering is maintained or reduced by means ofthe correction factor.
 15. The method for the air conditioning of avehicle interior as a function of incident solar radiation as claimed inclaim 12, wherein the selected multiplier is
 50. 16. The method for theair conditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 1, wherein during the determination of theair conditioning capacity on the basis of the incident solar radiation,the blow-in temperature is lowered and the blower power is raised, andthis raising/lowering is maintained or reduced by means of thecorrection factor.
 17. The method for the air conditioning of a vehicleinterior as a function of incident solar radiation as claimed in claim16, wherein the selected multiplier is
 50. 18. The method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 1, wherein during the determination of theair conditioning capacity on the basis of the incident solar radiation,the blow-in temperature is lowered or the blower power is raised, andthis raising/lowering is maintained or reduced by means of thecorrection factor.
 19. The method for the air conditioning of a vehicleinterior as a function of incident solar radiation as claimed in claim18, wherein the selected multiplier is
 50. 20. The method for the airconditioning of a vehicle interior as a function of incident solarradiation as claimed in claim 1, wherein the selected multiplier is 50.